In 2-cup measure, stir together juice, sugar, soy sauce, pepper flakes, garlic and gingerroot. Place chicken in gallon-sized heavy resealable plastic bag; pour marinade over chicken and seal. Refrigerate chicken mixture 2 to 24 hours, turning occasionally to keep chicken coated in marinade. Heat oven to 350ºF. Line 15 1/2 x 10 1/2 x 1-inch jelly roll pan with aluminum foil. Spray with nonstick spray. Remove chicken pieces from marinade; place in single layer on baking sheet. Bake uncovered 30 minutes; drain off accumulated juices and turn chicken. Increase temperature to 425ºF. Bake an additional 10 to 15 minutes or until juice of chicken is no longer pink and chicken is golden brown. Meanwhile, pour marinade into 1-quart saucepan. Heat to boiling; reduce heat and simmer, uncovered, over medium heat 15 - 25 minutes until mixture is reduced to about 1/3 cup and slightly thickened. When chicken is done, place chicken in large bowl. Drizzle reduced marinade over chicken. Stir until chicken is coated. Place on serving platter; sprinkle with green onions. Makes 8 servings (about 3 wings each).